I caught this little bit in the official site news blurb. Here are some of the cast:
"...will be joined by a fantastic new cast that includes Stellan Skarsgard, Adria Arjona, Fiona Shaw, Denise Gough, Kyle Soller, and Genevieve O’Reilly as Mon Mothma."
Glad to see Genevieve O'Reilly back in the mix. I think she's added some depth to the Mon Mothma character. And to think that she had the part in Revenge Of The Sith and got cut from the movie, but has parlayed it into voice acting on Rebels, a live action role in Rogue One and now this show, too!